Systems and methods for sequencing operation of compressed air dryers

ABSTRACT

Compressed air dryer systems are described. In an aspect, a system includes, but is not limited to, a plurality of dryer modules and a controller operable to regulate a run-time of each of the plurality of dryer modules. Each dryer module is configured to direct a portion of cooling medium past a stream of compressed air. Each dryer module includes a temperature sensor in thermal communication with the portion of cooling medium, and a chiller configured to reduce a temperature of the portion of cooling medium based on the sensed temperature and a temperature set-point. The controller communicatively is coupled with the plurality of dryer modules and operable to monitor a plurality of run-times. Each run-time is associated with a corresponding dryer module. The controller is further operable to direct operation of each dryer module based on its run-time by modifying the temperature set-point of the dryer module.

BACKGROUND

Compressed air systems can utilize heat exchange systems to drycompressed air by condensing and removing moisture to output a driedcompressed air stream. The heat exchange systems can use a coolingmedium to facilitate heat transfer from the compressed air to thecooling medium. The warmed cooling medium can then be discarded orrechilled for future use.

SUMMARY

Compressed air dryer systems are described. In an aspect, a systemincludes, but is not limited to, a storage tank, a single cooling mediumheader, a plurality of dryer modules, and a controller operable toregulate a run-time of each of the plurality of dryer modules. Thestorage tank is configured to hold a cooling medium in a fluid statewithin an interior of the storage tank. The single cooling medium headeris fluidically coupled with the storage tank. The plurality of dryermodules is fluidically coupled with each of the single cooling mediumheader and the storage tank. Each dryer module is configured to direct aportion of cooling medium received from the single cooling medium headerpast a stream of compressed air and back to the storage tank. Each dryermodule includes a temperature sensor in thermal communication with theportion of cooling medium and a chiller configured to reduce atemperature of the portion of cooling medium when the sensed temperatureexceeds a temperature set-point. The controller is communicativelycoupled with the plurality of dryer modules and operable to monitor aplurality of run-times. Each run-time is associated with a correspondingdryer module. The controller is further operable to regulate eachrun-time by modifying the temperature set-point of corresponding thedryer module.

In an aspect, a system includes, but is not limited to, a plurality ofdryer modules and a controller operable to regulate a run-time of eachof the plurality of dryer modules. Each dryer module is configured todirect a portion of cooling medium past a stream of compressed air tocondense at least a portion of moisture held in the first stream ofcompressed air. Each dryer module includes a temperature sensor inthermal communication with the portion of cooling medium, and a chillerconfigured to reduce a temperature of the portion of cooling mediumbased on the sensed temperature and a temperature set-point. Thecontroller communicatively is coupled with the plurality of dryermodules and operable to monitor a plurality of run-times. Each run-timeis associated with a corresponding dryer module. The controller isfurther operable to direct operation of each dryer module based on itsrun-time by modifying the temperature set-point of the dryer module.

In an aspect, a method for regulating the run-time of a plurality ofcompressed air dryer modules includes, but is not limited to, operatinga first dryer module, based on a first temperature set-point, toregulate a temperature of a first portion of cooling medium beingcirculated through the first dryer module; operating a second dryermodule, based on a second temperature set-point, to regulate atemperature of a second portion of cooling medium being circulatedthrough the second dryer module; monitoring, via a controller, a firstrun-time associated with operation of the first dryer module and asecond run-time associated with operation of the second dryer module;and modifying, via the controller, the first temperature set-point andthe second temperature set-point to regulate the first run-time and thesecond run-time, respectively.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

DRAWINGS

The Detailed Description is described with reference to the accompanyingfigures. The use of the same reference numbers in different instances inthe description and the figures may indicate similar or identical items.

FIG. 1 is a schematic illustration of a compressed air dryer system inaccordance with in accordance with embodiments of the presentdisclosure.

FIG. 2A is a diagram illustrating an example algorithm for regulatingrun-time of a compressed air dryer system, such as the compressed airdryer system of FIG. 1 , in accordance with embodiments of the presentdisclosure.

FIG. 2B is another diagram illustrating an example algorithm forregulating run-time of a compressed air dryer system, such as thecompressed air dryer system of FIG. 1 , in accordance with embodimentsof the present disclosure.

FIG. 2C is another diagram illustrating an example algorithm forregulating run-time of a compressed air dryer system, such as thecompressed air dryer system of FIG. 1 , in accordance with embodimentsof the present disclosure.

FIG. 3A is an example flow diagram illustrating an example process forregulating the run-time of a compressed air dryer system, such as thecompressed air dryer system illustrated in FIG. 1 , in accordance withan example implementation of the present disclosure.

FIG. 3B is another example flow diagram illustrating an example processfor regulating the run-time of a compressed air dryer system, such asthe compressed air dryer system illustrated in FIG. 1 , in accordancewith an example implementation of the present disclosure.

DETAILED DESCRIPTION Overview

Compressed air systems treat a source of air, such as environmental air,by compressing the air to provide a source of compressed air for workapplications. The air may have moisture present following treatment bythe compressed air system, such as due to humidity conditions in theenvironment supplying the source air. Moisture can be detrimental tovarious compressed air applications, such as by posing a risk formachines that utilize the compressed air, products treated byapplication of the compressed air, products produced with the compressedair, and the like. For example, moisture in compressed air cancontribute to risks for rust, corrosion, contamination, bacterialgrowth, dilution, and the like. To reduce the amount of moisture presentin compressed air, compressed air systems can include or be coupled withheat exchange systems to remove moisture through condensation ofmoisture and separation of the condensation from the flow of compressedair. The heat exchange systems can circulate a cooling medium, such aswater, glycol, synthetic refrigerant, or the like, to cool a flow ofcompressed air and heat the cooling medium. The heated cooling mediumcan then be discarded or chilled to provide cooling for futureapplications.

Compressed air systems can incorporate multiple heat exchange systemsfor drying multiple flows of compressed air. For example, compressed airsystems can include multiple dryer modules that share a source ofcooling medium that is circulated through the modules, and/or multipleindependent dryer modules. For systems that share a source of coolingmedium, the cooling medium can be stored in a storage tank for transferto the individual dryer modules by one or more pumps. As the dryermodules treat the compressed air, the cooling medium is heated duringcondensation of the moisture and then subsequently cooled (e.g., by achiller) and transferred back to the storage tank.

The number of dryer modules in operation may vary based on a loadcondition of the compressed air system. The system will operate with theminimum number of dryer modules necessary to meet the total compressedair demand. At low load conditions, for example, one module (e.g., thelead module) may be sufficient to meet the compressed air demand of thesystem, and will operate more frequently than the other dryer modules tomaintain a desired temperature of the cooling medium. As the system loadincreases, additional dryer modules are engaged sequentially to meet theincreased compressed air demand. A large compressed air system mayoperate most frequently at lower load conditions (e.g., nights,weekends, etc.), operating at near full capacity less than 45 percent ofthe time. Because the dryer modules are engaged sequentially based onthe load condition of the system, the run-time (e.g., run-hours) of eachdryer module varies, with some dyer modules (e.g., the lead module)operating more frequently than other modules. This disparate run-timebetween dryer modules results in varied mechanical and electrical wearon the dryer modules and their components, and can decrease theoperating life of modules with high run-time.

Accordingly, the present disclosure is directed, at least in part, tosystems and methods for regulating run-time in compressed air systemsoperating multiple dryer modules. In an aspect, each of the dryermodules includes a temperature sensor in thermal communication with thecooling medium circulating through the dryer module; and a chillerconfigured to reduce a temperature of the portion of cooling mediumbased on the sensed temperature and a temperature set-point. Acontroller is operable to monitor the run-time (e.g., run hours) of eachof the dryer modules. The controller regulates operation of each of thedryer modules based on its run-time by modifying the temperatureset-point of the dryer modules. In some aspects, each dryer module willhave a unique temperature set-point selected to match the requiredcooling load of the system, and the dryer modules will operatesequentially based on a hierarchy of temperature set-points. Bymodifying the temperature set-points, the controller is operable toadjust each dryer module’s position in the sequence of operation toachieve a desired run-time for each module, for example, to achieveequivalent run-time of the dryer modules. Operating the dryer moduleswith run-time can facilitate uniform mechanical and electrical wear onthe modules, enhancing the reliability and operating life of each moduleand its components, and reducing the incidence of premature modulefailures.

Example Implementations

Referring generally to FIG. 1 , a compressed air dryer system 100 forregulating run-time of a plurality of dryer modules for drying aplurality of compressed air streams is described in accordance withexample embodiments of the present disclosure. In some embodiments, thesystem 100 includes a shared cooling medium that is distributed to theplurality of drying modules. The system 100 is shown including a storagetank 102, a circulation pump 104, a cooling medium header 106, a dryermodule 108, a circulation pump 204, and a dryer module 208. The system100 distributes a cooling medium from the storage tank 102 to thecooling medium header 106 for supply to each dryer module fluidicallycoupled with the cooling medium header 106 to condense moisture carriedin flows of compressed air through the dryer modules. In FIG. 1 , eachof dryer module 108 and dryer module 208 are fluidically coupled withthe cooling medium header 106 to receive cooling medium flowedtherethrough. While FIG. 1 shows two dryer modules fluidically coupledwith the cooling medium header 106 (e.g., dryer module 108 and dryermodule 208), the system 100 is not limited to such configurations. Forinstance, the system 100 can include more than two dryer modulesfluidically coupled with the cooling medium header 106, including, butnot limited to, three dryer modules, four dryer modules, five dryermodules, six dryer modules, seven dryer modules, eight dryer modules,more than eight dryer modules, or the like.

The storage tank 102 holds a volume of cooling medium suitable fordistribution throughout the system 100 to condense moisture carried inflows of compressed air through the dryer modules. The capacity of thestorage tank 102 can depend on the type of cooling medium utilized, thenumber of dryer modules, the throughput of compressed gas processed bythe system 100, and the like. In example implementations, the storagetank 102 holds a volume of approximately 70 gallons to approximately 300gallons to support from two to eight dryer modules for an air capacityof approximately 3,500 standard cubic feet per minute (SCFM) ofcompressed air to approximately 25,000 SCFM of compressed air.Alternatively or additionally, the system 100 can include a plurality ofstorage tanks 102 to store cooling medium for the dryer modules, forexample, where a first storage tank 102 can provide cooling medium to afirst subset dryer modules of the system 100, a second storage tank 102can provide cooling medium to a second subset dryer modules of thesystem 100, and so on. In implementations, the plurality of storagetanks 102 include a single common cooling medium header 106.Alternatively, the plurality of storage tanks 102 include differentcooling medium headers 106 for the individual subsets of dryer modules.

The storage tank 102 stores the cooling medium following refrigerationof the cooling medium by the dryer modules. In implementations, thestorage tank 102 is thermally insulated to maintain the cooling mediumat a cold temperature to provide a pressure dew point in the dryermodules from about 40° F. to about 32° F. The cooling medium caninclude, but is not limited to, a glycol-based medium (e.g., propyleneglycol, ethylene glycol, etc.), water, a synthetic refrigerant, orcombinations thereof. For example, the cooling medium can include ablend of glycol with water in a volumetric ratio of about 1:2.

A plurality of circulation pumps draws cooling medium from the storagetank 102 and supplies the cooling medium to the cooling medium header106. While FIG. 1 shows two circulation pumps coupled between thestorage tank 102 and the cooling medium header 106 (e.g., circulationpump 104 and circulation pump 204), the system 100 is not limited tosuch configurations. For instance, the system 100 can include more thantwo circulation pumps fluidically coupled between the storage tank 102and the cooling medium header 106, including, but not limited to, threecirculation pumps, four circulation pumps, five circulation pumps, sixcirculation pumps, seven circulation pumps, eight circulation pumps,more than eight circulation pumps, or the like. In implementations, thesystem 100 includes one or more pumps for each dryer module fluidicallycoupled with the storage tank 102. Multiple circulation pumps canprovide redundancy of flow of cooling medium to the cooling mediumheader 106, which can ensure continuous flow of cooling medium in eventswhere one or more circulation pumps are offline or otherwise not pumpingfluid (e.g., during a maintenance activity, loss of power, failure ofone or more components, etc.).

In implementations, each circulation pump is fluidically coupled to eachof the storage tank 102 and the cooling medium header 106 via individualfluid lines to supply the cooling medium to the cooling medium header106 through each of the individual fluid lines during operation of therespective circulation pumps. For example, the circulation pump 104 isfluidically coupled with the storage tank 102 via fluid line 110 andwith the cooling medium header 106 via fluid line 112, and thecirculation pump 204 is fluidically coupled with the storage tank 102via fluid line 210 and with the cooling medium header 106 via fluid line212. In implementations, each of the circulation pumps is operated on acontinuous basis to continuously draw cooling medium from the storagetank 102 and direct the cooling medium into the cooling medium header106. The system can include valves to isolate the circulation pumpsduring service, to control fluid direction of cooling medium, or thelike. For example, the system can include valve 114 between thecirculation pump 104 and the storage tank 102, valve 116 between thecirculation pump 104 and the cooling medium header 106, valve 214between the circulation pump 204 and the storage tank 102, valve 216between the circulation pump 204 and the cooling medium header 106, orcombinations thereof.

As shown in FIG. 1 , the system 100 can include a single cooling mediumheader (e.g., cooling medium header 106) during circulation of thecooling medium throughout the system 100. For example, inimplementations, the cooling medium made available to the dryer modulesand received from the dryer modules is combined in two regions of thesystem 100. First, the cooling medium is stored and mixed in the storagetank 102. Second, the cooling medium is stored and mixed in the coolingmedium header 106 to be made available to each of the dryer module 108and the dryer module 208. Other regions of the system 100 separate thecooling medium within confined flow paths (e.g., fluid lines 110 and112, fluid lines 210 and 212, within the dryer module 108, within thedryer module 208, transferred from the dryer module 108 to the storagetank 102, transferred from the dryer module 208 to the storage tank102). The cooling medium header 106 receives cooling medium from each ofthe circulation pump 104 and the circulation pump 204, where the coolingmedium is permitted to span the length of the cooling medium header 106to be available to each of the dryer module 108 and the dryer module 208at the same inlet temperature. The system 100 permits mixture of thecooling medium in the storage tank 102 following receipt from the dryermodules 108 and 208 to provide an initial mixing of streams of coolingmedium that may be at different temperatures dependent on the dutyexperienced by the dryer modules 108 and 208 (e.g., proportional to theflow of compressed air through the respective dryer modules). Thecooling medium can again mix in the cooling medium header 106 prior totransfer to the dryer module 108 or the dryer module 208. The coolingmedium header 106 can be dimensioned based on the volumetric flow ofcooling medium through the system 100, based on the number of dryermodules serviced by the storage tank 102, or the like. Inimplementations, the cooling medium header 106 includes a capped conduithaving an inner diameter from about two inches to about twelve inches,however the system 100 is not limited to such dimensions and can havelarger or smaller diameters for the cooling medium header 106 dependenton system throughput.

The dryer modules of the system 100 receive cooling medium from thecooling medium header 106 through individual fluid lines for each dryermodule and output used cooling medium to the storage tank 102 throughindividual fluid lines for each dryer module. For example, dryer module108 receives cooling medium from the cooling medium header 106 via fluidline 118 and transfers cooling medium (e.g., cooling medium having beenheated by heat exchange with compressed air within the dryer module 108)to the storage tank 102 via fluid line 120, whereas dryer module 208receives cooling medium from the cooling medium header 106 via fluidline 218 and transfers cooling medium (e.g., cooling medium having beenheated by heat exchange with compressed air within the dryer module 208)to the storage tank 102 via fluid line 220.

In implementations, the dryer modules first direct the cooling mediumreceived from the cooling medium header 106 into one or more heatexchangers to transfer heat from a stream of compressed air to thecooling medium to cool the compressed air, condense moisture held by thecompressed air, and warm the cooling medium. For example, the dryermodule 108 directs cooling medium from fluid line 118 into a heatexchanger 122 having an input stream 124 of compressed air that passesby a separated flow of cooling medium to condense moisture held in thecompressed air and dry the compressed air for output at 126. Similarly,the dryer module 208 directs cooling medium from fluid line 218 into aheat exchanger 222 having an input stream 224 of compressed air thatpasses by a separated flow of cooling medium to condense moisture heldin the compressed air and dry the compressed air for output at 226. Thecondensation separated from the compressed air is then removed from thedryer module, such as through an air/moisture separator, water trap, orother separation system.

Warmed cooling medium (or chilled cooling medium if no flow ofcompressed air is circulated within the dryer module) is transferredfrom the heat exchanger to a chiller that cools cooling medium inpreparation for transfer back to the storage tank 102. For example, thedryer module 108 directs cooling medium from the heat exchanger 122 to achiller 128 via fluid line 130, and the dryer module 208 directs coolingmedium from the heat exchanger 222 to a chiller 228 via fluid line 230.The chillers 128 and 228 can include compressors, condensers, thermalexpansions valves, or the like, or combinations thereof, to chill thecooling medium for output to the storage tank 102 via fluid lines 120and 220, respectively.

In implementations, the dryer modules include temperature sensors (e.g.,thermistors, thermocouple, etc.) to determine a temperature of coolingmedium to control operation of the chillers. For example, the dryermodule 108, 208 can include a temperature sensor in thermalcommunication with the cooling medium to determine a temperature ofcooling medium leaving the heat exchanger 122, 222, where a controller(e.g., module controller 132, 232) of the dryer module 108, 208 directsoperation of the chiller 128, 228 to cool the cooling medium if thetemperature meets a threshold temperature (e.g., a temperatureset-point) for the module 108, 208. It is to be understood thatterminology “meeting a threshold temperature” is meant to includemeeting or exceeding the temperature set-point. In a specificimplementation, the module controller 132, 232 monitors the temperatureof the cooling medium that is being circulated to the heat exchanger122, 222 and will then activate operation of the chiller 128, 228 as thetemperature rises above the desired temperature set-point for eachmodule 108, 208. Once the temperature of the cooling medium returns tothe temperature set-point, the module controller 132, 232 deactivatesoperation of the chiller 128, 228.

In some implementations, each dryer module 108, 208 will have a uniquetemperature set-point selected to match the required cooling load of thesystem 100, and the dryer modules 108, 208 will operate sequentiallybased on a hierarchy of temperature set-points. For example, operationof dryer module 108 is directed based on a first temperature set-point(e.g., a base temperature set-point), and operation of dryer module 208is directed based on a second temperature set-point that is offset fromthe base temperature set-point. Dryer module 108 will be activated firstwhen the temperature of the cooling medium reaches (or exceeds) the basetemperature set-point, and dryer module 208 will be subsequentlyactivated when the temperature of the cooling medium meets (or exceeds)the second temperature set-point. In such implementations, the dryermodule with the lowest temperature set-point (e.g., the lead module)will have the highest operating frequency, while the dryer module withthe highest temperature set-point will have the lowest operatingfrequency.

In some implementations, the offset temperature set-point(s) aredetermined based on a temperature differential between each module. Forexample, there may be an operating temperature differential of 0.5° F.,1.0° F., 1.5° F., 2.0° F., 2.5° F., 3.0° F., 3.5° F., 4.0° F., 4.5° F.,5.0° F., or the like, between each dryer module. In a specificembodiment, the first dryer module 108 has a base temperature set-point,and the second dryer module 208 has a temperature set-point of the basetemperature set-point plus the operating temperature differential.Depending on the number of dryer modules and the load requirements ofthe system 100, the operating temperature differential may be a fixedtemperature differential, an incremental temperature differential, or anexponential temperature differential. As the load of the system 100increases, dryer modules are sequentially activated based on thenext-lowest temperature set-point to meet the total compressed airdemand. It is to be understood that while the dyer modules are generallyactivated sequentially as the load of the system 100 increases, thetotal compressed air demand may necessitate that two or more dryermodules be activated simultaneously. Such simultaneous activation can beachieved by assigning the same temperature set-point to the dryermodules.

Alternatively or additionally, the storage tank 102 or another portionof the system 100 can include one or more temperature sensors to controloperation of the chillers 128, 228.

In implementations, the system 100 includes a controller 134 that isoperable to regulate the run-time of each of the dryer modules 108, 208.For example, the system can include a selected run-time threshold (e.g.,operating hour set-point) for the dryer modules 108, 208. Inimplementations, the run-time threshold can be selected by an operatorof the system 100 or preconfigured by a manufacturer. In a specificimplementation, the run-time threshold is in the range of 500 hours to1,000 hours. The controller 134 is operable to monitor a plurality ofrun-times (e.g., run-hours), each associated with one of the dryermodules 108, 208, and determine when the run-time threshold is met. Forexample, the controller 134 can compare the run-time of each dryermodule 108, 208 to the run-time threshold and determine if the run-timethreshold has been met or exceeded. When the controller 134 determinesthat the dyer module 108, 208 run-time meets the run-time threshold, thecontroller 134 directs deactivation of the module 108, 208, for exampleby deactivating the respective chiller 128, 228. It is to be understoodthat the terminology “determining when the run-time threshold is met”and “meeting the run-time threshold” are meant to include meeting orexceeding the run-time threshold.

In a specific implementation, the system 100 utilizes the techniquesdescribed herein to direct operation of the dryer modules 108, 208 suchthat the run-time for the modules 108, 208 is substantially equivalent.Operating the dryer modules 108, 208 with an equivalent number ofrun-hours can facilitate uniform mechanical and electrical wear on themodules 108, 208, enhancing the reliability and operating life of eachmodule 108, 208 and its components, and reducing the incidence ofpremature module failures.

In implementations, the controller 134 includes a sequencer operable toregulate the run-time of the dryer modules 108, 208 by modifying thetemperature set-point of each module 108, 208. For example, when therun-time of a dryer module 108, 208 meets the run-time threshold, thecontroller 134 directs operation of the dyer modules 108, 208 byincreasing the temperature set-point of the module 108, 208 such thatthe respective chiller 128, 228 is deactivated. In implementations, whenthe run-time for a dryer module meets the run-time threshold thesequencer is operable to modify the temperature set-points for each ofthe dryer modules based on the run-time for each module. For example,when the lead module reaches the run-time threshold, the sequencer isoperable to reset the temperature set-point of the lead module to thebottom of the temperature hierarchy (e.g., by increasing the temperatureset-point to the highest temperature set-point of the group of modules).The sequencer is further operable to reset the temperature set-points ofthe remaining dryer modules, moving each temperature set-point upwardsin the temperature hierarchy (e.g., by decreasing the temperatureset-point for the respective module) such that the module withnext-highest run-time becomes the new lead module. Once a lead module(s)reaches the run-time threshold and is deactivated, the run-time for thatmodule is reset (e.g., to 0 hours). In such implementations, thecontroller 134 directs operation of the dryer modules such that themodule with the highest run-time operates at the highest frequency untilthe run-time threshold is met.

In some implementations, the sequencer can regulate operation of thedryer modules 108, 208 based on other system load considerations. Forexample, the controller 134 can direct operation of the dryer modules108, 208 by modifying the temperature set-point based on time-of-day orother load monitoring parameters to reduce run-time during low loadperiods.

While FIG. 1 shows controller 134 as an independent control separatefrom the individual module controllers 132, 232, the system 100 is notlimited to such configurations. Alternatively, part or all of thefunctionality of controller 134 may be integrated into one or more ofthe module controllers 132, 232. Likewise, part or all of thefunctionality of the module controllers 132, 232 may be integrated intoone or more independent controllers. The controller 134 and/or themodule controllers 132, 232 can control the components and functions ofsystems 100 described herein using software, firmware, hardware (e.g.,fixed logic circuitry), manual processing, or a combination thereof. Theterms “controller,” “functionality,” “service,” and “logic” as usedherein generally represent software, firmware, hardware, or acombination of software, firmware, or hardware in conjunction withcontrolling the systems 100. In the case of a software implementation,the module, functionality, or logic represents program code thatperforms specified tasks when executed on a processor (e.g., centralprocessing unit (CPU) or CPUs). The program code can be stored in one ormore computer-readable memory devices (e.g., internal memory and/or oneor more tangible media), and so on. The structures, functions,approaches, and techniques described herein can be implemented on avariety of commercial computing platforms having a variety ofprocessors. It is to be understood the that the controller 134 and/orthe module controllers 132, 232 can include any number ofmicrocontrollers, processors, and/or resident or external memory.

In configurations where controller 134 functions as an independentcontroller in communication with module controllers 132, 232, controller134 can be operable to monitor additional operating parametersassociated with the individual controllers 132, 232. For example, thecontroller 134 can monitor a fault condition associated with modulecontroller 132, 232 to identify a defective dryer module. Similarly, thecontroller 134 can monitor a maintenance condition (e.g., a filter wearcondition, drain condition, etc.) associated with module controller 132,232 to identify a dryer module requiring maintenance. Based onidentification of a fault condition and/or a maintenance, the controller134 may be operable to deactivate the corresponding dryer module and/orits components (e.g., chillers), for example, by directing operation ofa switch (e.g., electrical switch, pneumatic switch, etc.), valve, orthe like of the dyer module. In a specific implementation, thecontroller 134 directs operation of an electrical switch output or a lowvoltage communications interface to deactivate the dryer module.Alternatively or additionally, the controller 134 can direct operationof an electrical or pneumatic switch to energize a shut-off airisolation valve, thereby preventing compressed airflow through the dryermodule.

In implementations, the controller 134 can be communicatively coupledwith the dryer modules 108, 208 over a communication network. It isfurther contemplated that dryer module 108 is can be communicativelycoupled with dryer module 208 over the communications network. Thecommunication network may comprise a variety of different types ofnetworks and connections that are contemplated, including, but notlimited to: wired and/or wireless connections; the Internet; anintranet; a satellite network; a cellular network; a mobile datanetwork; and so forth. Wired communications are contemplated throughuniversal serial bus (USB), RS-485, Ethernet, BACnet, Profibus, serialconnections, and so forth. Wireless communications are also contemplatedthrough wireless networks including, but are not limited to: networksconfigured for communications according to: one or more standard of theInstitute of Electrical and Electronics Engineers (IEEE), such as 802.11or 802.16 (Wi-Max) standards; Wi-Fi standards promulgated by the Wi-FiAlliance; Bluetooth standards promulgated by the Bluetooth SpecialInterest Group; and so on. In a specific implementation, the controller134 can monitor each dryer module 108, 208 via a wired communicationsnetwork that is wired in sequence between each of the modules 108, 208.

In implementations, the controller 134 and/or the module controllers132, 232 can include a user interface for receiving operator input anddisplaying information to the operator. For example, the user interfacemay include a display such as an LCD (Liquid Crystal Diode) display, aTFT (Thin Film Transistor) LCD display, an LEP (Light Emitting Polymer)or PLED (Polymer Light Emitting Diode) display, and so forth, configuredto display text and/or graphical information such as a graphical userinterface. The user interface can also include one or more input/output(I/O) devices (e.g., a keypad, buttons, a wireless input device, athumbwheel input device, a touchscreen, and so on). The I/O devices mayinclude one or more audio I/O devices, such as a microphone, speakers,and so on.

It is to be understood that while FIG. 1 shows multiple dryer modules108, 208 with a shared storage tank 102 of cooling medium, the system100 is not limited to such configurations. Alternatively oradditionally, the system 100 can include multiple independent dryermodules that do not share a common store of cooling medium.

FIGS. 2A through 2C illustrate example algorithms that are executable bythe controller 134 (e.g., via the sequencer) for determining thetemperature set-points for the plurality of dryer modules. The sequenceris operable to execute one or more algorithms or commands to determine atemperature set-point for each dryer module based on the selected basetemperature set-point, the selected temperature differential, and theselected number of dryer modules (e.g., as described with reference toFIG. 2A). Based on the number of modules selected, the sequencerdetermines the temperature set-point for each module by applying anoffset from the base temperature set-point that is based on thetemperature differential. For example, when two dryer modules areselected, the first module is directed to become operational at the basetemperature set-point (SP), and the second dryer module is directed tobecome operational at an offset temperature set-point based on theselected temperature differential (SP + 3*Diff). The sequencer isfurther operable to execute one or more algorithms or commands todetermine a temperature vector ordering the modules in an operatinghierarchy based on the temperature set-points (e.g., as described withreference to FIG. 2B). For example, the dryer modules may be arranged ina hierarchy of ascending temperatures such that the lead dryer module(e.g., module 1) is activated at the base temperature set-point, and theother dryer modules are activated in order of ascending temperatureset-point. The sequencer is further operable to monitor the run-time(e.g., run hours) of each dryer module and execute one or morealgorithms or commands to modify the temperature set-point of eachmodule such that the modules are rotated through the operating hierarchybased on run-time (e.g., as described with reference to FIG. 2C). Forexample, when module 1 reaches or exceeds the run-time threshold, thesequencer modifies the temperature set-points of the dryer modules suchthat module is moved to the bottom of the operating hierarchy. In suchimplementations, the temperature set-point of the lead module (e.g.,module 1) is reset to the highest temperature set-point of thetemperature vector. The temperature set-points of the other dryermodules are reset such that these modules are moved up the operatinghierarchy and the module with the next-highest run-time (e.g., module 2)becomes the lead module with the lowest temperature set-point (e.g., thebase temperature set-point). As described above, the total compressedair demand of the system 100 may necessitate that two or more dryermodules be activated simultaneously. As shown in FIGS. 2A through 2C,the sequencer may assign the same temperature set-point to two or moredryer modules to achieve such simultaneous activation needs.

FIGS. 3A and 3B illustrate an example process 300 for regulating therun-time of a plurality dryer modules utilizing a compressed air dryersystem, such as the compressed air dryer system 100 described above. Asshown in FIG. 3A, a selection of a desired number of dryer modules isreceived (Block 302). In implementations, the desired number of dryermodules can be based on the required cooling-load of the system. Forexample, under low-load conditions (e.g., evenings, weekends), it may bedesirable to utilize fewer dryer modules. The selection of the number ofmodules can be received as operator input (e.g., via the userinterface), and/or as a preconfigured manufacturer setting.

A selection of a run-time threshold is received (Block 304). Asdescribed above with reference to FIG. 1 , the run-time threshold is adesired run-time limit (e.g., operating hour set-point) for each of thedryer modules 108, 208. In a specific implementation, the run-timethreshold is in the range of 500 hours to 1,000 hours. In someimplementations, the run-time threshold is selected based operatingrequirements of the system 100 including, but not limited to system loadrequirements, compressed air demand, mechanical specifications of thedryer modules, and so forth. The selection of the run-time threshold canbe received as operator input (e.g., via the user interface), and/or asa preconfigured manufacturer setting.

A selection of a base temperature set-point and a temperaturedifferential is received (Block 306). As described with reference toFIG. 1 , each dryer module 108, 208 will have a unique temperatureset-point selected to match the required cooling load of the system 100,and the dryer modules 108, 208 will operate sequentially based on ahierarchy of temperature set-points. For example, operation of dryermodule 108 is directed based on a first temperature set-point (e.g., abase temperature set-point). Operation of dryer module 208 is directedbased on a second temperature set-point that is offset from the basetemperature set-point based on a selected temperature differential. Forexample, dryer module 208 can have a temperature set-point of the basetemperature set-point plus the operating temperature differential. Asdescribed above, depending on the number of dryer modules and the loadrequirements of the system 100, the operating temperature differentialmay be a fixed temperature differential, an incremental temperaturedifferential, or an exponential temperature differential. The selectionof the base temperature set-point and the temperature differential canbe received as operator input (e.g., via the user interface), and/or aspreconfigured manufacturer settings.

A temperature set-point for each of a plurality of dryer modules isdetermined based on the base temperature set-point, the temperaturedifferential, and the selected number of dryer modules (Block 308). Asdescribed above, based on the number of modules selected, a sequencerdetermines the temperature set-point for each module by applying anoffset from the base temperature set-point that is based on thetemperature differential (e.g., as described with reference to FIG. 2A).A temperature order vector is determined based on the temperatureset-points and the selected number of dryer modules (Block 310). Asdescribed above, the dryer modules can be arranged in a hierarchy ofascending temperatures such that the lead dryer module (e.g., module 1)is activated at the base temperature set-point, and the other dryermodules are activated in order of ascending temperature set-point (e.g.,as described with reference to FIG. 2B).

In some implementations, the temperature set-point for each dryer moduleis transmitted to the respective dryer module (Block 312). As describedabove with reference to FIG. 1 , the sequencer can be included in anindependent controller 134 that is operable to transmit the temperatureset-point for each dryer module 108, 208 to the module controller 132,232 corresponding to the module 108, 208 via the communication network(e.g., a wired and/or wireless network). In other embodiments, thesequencer may be integrated into one or more of the module controllers132, 232.

The run-time for each dryer module is monitored (Block 314). Asdescribed above with reference to FIG. 1 , the controller 134 isoperable to monitor a plurality of run-times (e.g., run-hours), eachassociated with one of the dryer modules 108, 208. The system candetermine when the run-time for a dryer module meets the run-timethreshold (Block 316). As described above with reference to FIG. 1 , thecontroller 134 is operable to compare the run-time of each dryer module108, 208 to the run-time threshold and determine if the run-timethreshold has been met or exceeded.

When a dryer module meets the run-time threshold, the temperatureset-points for the dryer modules are modified based on the temperatureorder vector (Block 318). As described above, when a dryer module (e.g.,the lead module) reaches or exceeds the run-time threshold, thesequencer is operable to modify the temperature set-points of the dryermodules such that lead module is moved to the bottom of the operatinghierarchy (e.g., as described with reference to FIG. 2C). In suchimplementations, the temperature set-point of the lead module (e.g.,module 1) is reset to the highest temperature set-point of thetemperature vector. The temperature set-points of the other dryermodules are reset such that these modules are moved up the operatinghierarchy and the module with the next-highest run-time (e.g., module 2)becomes the lead module with the lowest temperature set-point (e.g., thebase temperature set-point). In some implementations, the newtemperature set-point for each dryer module is transmitted to therespective dryer module (Block 320).

Although the subject matter has been described in language specific tostructural features and/or process operations, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims.

1-20. (canceled)
 21. A compressed air dryer system, the systemcomprising: a cooling medium header; and a plurality of dryer modulesfluidically coupled with the cooling medium header, each of theplurality of dryer modules configured to direct a portion of a coolingmedium received from the cooling medium header through a heat exchangerand to a storage tank, the heat exchanger configured to transfer heatfrom a portion of compressed air to the portion of the cooling medium,each of the plurality of dryer modules including: a temperature sensorin thermal communication with the portion of cooling medium, and achiller configured to reduce a temperature of the portion of coolingmedium when the sensed temperature exceeds a temperature set-point; anda controller communicatively coupled with the plurality of dryermodules, the controller operable to monitor a plurality of run-times,each of the plurality of run-times associated with a corresponding oneof the plurality of dryer modules, the controller operable to regulateeach of the plurality of run-times by modifying the temperatureset-point of the corresponding one of the plurality of dryer modules.22. The system of claim 21, wherein the controller is configured toregulate operation of each of the plurality of dryer modules such thateach of the plurality of run-times are equivalent.
 23. The system ofclaim 21, wherein the controller is configured to regulate each of theplurality of run-times based on a run-time threshold.
 24. The system ofclaim 23, wherein the controller is configured to operate each of theplurality of dyer modules sequentially such that a one of the pluralityof dryer modules having the highest run-time is operated at the highestfrequency until the run-time threshold is met.
 25. The system of claim23, wherein the controller is configured to deactivate one of theplurality of dryer modules when the corresponding one of the pluralityof run-times is equal to the run-time threshold.
 26. The system of claim25, wherein the controller is further configured to reset thetemperature set-point for the corresponding one of the plurality ofdryer modules to a temperature set-point that is the highest temperatureset-point of the temperature set-points for the plurality of dryermodules.
 27. The system of claim 21, wherein the temperature set-pointfor one or more of the plurality of dryer modules is based on at leastone of a fixed operating temperature differential, an incrementaloperating temperature differential, or an exponential operatingtemperature differential.
 28. A compressed air dryer system, the systemcomprising: a plurality of dryer modules, each of the plurality of dryermodules configured to condense at least a portion of moisture held in aportion of compressed air, each of the plurality of dryer modulesincluding: a temperature sensor in thermal communication with theportion of cooling medium, and a chiller configured to reduce atemperature of the portion of cooling medium based on the sensedtemperature and a temperature set-point; and a controllercommunicatively coupled with the plurality of dryer modules, thecontroller operable to monitor a plurality of run-times, each of theplurality of run-times associated with a corresponding one of theplurality of dryer modules, the controller operable to direct operationof each of the plurality of dryer modules based on the corresponding oneof the plurality of run-times by modifying the temperature set-point ofthe corresponding one of the plurality of dryer modules.
 29. The systemof claim 28, wherein each of the plurality of dryer modules furtherincludes a module controller configured to regulate operation of thechiller based on the temperature set-point.
 30. The system of claim 28,wherein the temperature set-point for one or more of the plurality ofdryer modules is based on at least one of a fixed operating temperaturedifferential, an incremental operating temperature differential, or anexponential operating temperature differential.
 31. The system of claim28, wherein the controller is configured to regulate operation of eachof the plurality of dryer modules such that each of the plurality ofrun-times are equivalent.
 32. The system of claim 28, wherein thecontroller is configured to regulate operation of each of the pluralityof dryer modules based on a run-time threshold.
 33. The system of claim32, wherein the controller is configured to operate each of theplurality of dyer modules sequentially such that a one of the pluralityof dryer modules having the highest run-time is operated at the highestfrequency until the run-time threshold is met.
 34. The system of claim32, wherein the controller is configured to deactivate one of theplurality of dryer modules when the corresponding one of the pluralityof run-times is equal to the run-time threshold.
 35. The system of claim34, wherein the controller is configured to reset the temperatureset-point for the one of the plurality of dryer modules to a temperatureset-point that is the highest temperature set-point of the temperatureset-points for the plurality of dryer modules.
 36. A method forregulating run-time of compressed air dryer modules, the methodcomprising: operating a first dryer module, based on a first temperatureset-point, to regulate a temperature of a first portion of coolingmedium being circulated through the first dryer module; operating asecond dryer module, based on a second temperature set-point, toregulate a temperature of a second portion of cooling medium beingcirculated through the second dryer module; monitoring, via acontroller, a first run-time associated with operation of the firstdryer module and a second run-time associated with operation of thesecond dryer module; and modifying, via the controller, at least one ofthe first temperature set-point and the second temperature set-point toregulate at least one of the first run-time and the second run-time,respectively.
 37. The method of claim 36, further comprising: sensingthe temperature of the first portion of cooling medium via a firsttemperature sensor in thermal communication with the first portion ofcooling medium; operating a first chiller to reduce the temperature ofthe first portion of cooling medium based on the sensed temperatureobtained from the first temperature sensor; sensing the temperature ofthe second portion of cooling medium via a second temperature sensor inthermal communication with the second portion of cooling medium; andoperating a second chiller to reduce the temperature of the secondportion of cooling medium based on the sensed temperature obtained fromthe second temperature sensor.
 38. The method of claim 38, wherein themodifying at least one of the first temperature set-point and the secondtemperature set-point to regulate at least one of the first run-time andthe second run-time includes modifying at least one of the firsttemperature set-point and the second temperature set-point to regulateoperation at least one of the first chiller and the second chiller,respectively.
 39. The method of claim 36, wherein regulating at leastone of the first run-time and the second run-time includes regulatingoperation of at least one of the first dryer module and the second dryermodule based on a run-time threshold.
 40. The method of claim 36,wherein regulating at least one of the first run-time and the secondrun-time includes regulating operation regulating at least one of thefirst dryer module and the second dryer module such that the first runtime and the second run-time are equivalent.